Actor Shadows. Setting this to None disables shadows for other models. Blob enables simple circular shadows. Projected will enable volumetric shadows. Enabling shadows will reduce performance, particularly when set to Projected. This will also cause a higher performance drop than enabling shadows for the player.
Min Desired Framerate. Set this to equal to whatever you feel is the minimum for a playable game. 30 should be the ideal minimum frame rate for most users. This specifies the frame rate threshold below which Rune will start dropping detail - reducing model detail and not drawing optional effects. If this is set higher than your normal frame rate, then you will never see reduced graphics almost always, but get the best possible performance. The ideal setting for this is about 10 frames below your average frame rate, otherwise you'll drop off too much detail.
When benchmarking it would be best to set this to 0 to give a more accurate indication of real performance (see later on in the guide for how to benchmark Rune).